The goal of this project is to develop an electrochemical capacitor for implantable defibrillators. with an energy density exceeding 4 joules per cm 3 with an operating potential between 600 to 750 V, and with the capability of releasing up to 40 joules during a 20 msec discharge period. Giner, Inc. has extensive experience in the development of high energy density and high power density electrochemical capacitors using its patented proton exchange membrane technology. These capacitors are very stable, maintenance- free, have a long life, and contain no toxic or corrosive materials. nor are any toxic reaction products formed. In Phase lit was demonstrated that it is not only feasible to reach the stated requirements, but that it seems to be possible to significantly exceed them. During the Phase Il project. it is planned to develop and fabricate complete capacitor stack prototype devices and perform statistical testing. short- and long-term life tests. as well as failure mode and effect studies. In addition. it is planned during Phase II to prepare. together with a corporate partner. packaging and interface specifications. Capacitor fabrication process standardization and electronic interface and system integration will be performed within the final Phase III product engineering program. PROPOSED COMMERCIAL APPLICATIONS The commercial potential of this application is significant, not only since implantable device companies are in need of the proposed device. but also, because this technology would offer the capability of making other implantable support devices. i.e., for nerve and muscle stimulation. possible. this helping to increase. worldwide. the market share of US companies in these device segments.